Nucleic acid/ polysaccharide complex

Abstract

An object of the present invention is to provide a highly stable nucleic acid-polysaccharide complex of an siRNA and schizophyllan. A nucleic acid-polysaccharide complex is formed by adding polydeoxyadenine in which at least part of the phosphodiester link portion is phosphorothioated to an siRNA and allowing the siRNA and schizophyllan to form a complex.

1 . A nucleic acid-polysaccharide complex of schizophyllan and a polynucleotide,
 the polynucleotide containing an siRNA to which polydeoxyadenine is added,   the siRNA being directed to a target gene, and   the polydeoxyadenine having phosphodiester links that are at least partially phosphorothioated.   
     
     
         2 . The nucleic acid-polysaccharide complex according to  claim 1 , wherein the siRNA is a 21 mer type, and the polynucleotide contains polydeoxyadenine that has phosphodiester links at least partially phosphorothioated and that is added to a sense strand of the siRNA. 
     
     
         3 . The nucleic acid-polysaccharide complex according to  claim 1 , wherein the polydeoxyadenine has 30 to 50 nucleotides. 
     
     
         4 . The nucleic acid-polysaccharide complex according to  claim 1 , wherein at least 50% of the phosphodiester links of the polydeoxyadenine are phosphorothioated. 
     
     
         5 . The nucleic acid-polysaccharide complex according to  claim 1 , wherein the target gene is a gene expressed in a Dectin-1 expressing cell. 
     
     
         6 . The nucleic acid-polysaccharide complex according to  claim 1 , wherein the target gene is a costimulatory factor expressed in a Dectin-1 expressing cell. 
     
     
         7 . The nucleic acid-polysaccharide complex according to  claim 6 , wherein the costimulatory factor is a CD40 gene. 
     
     
         8 . A pharmaceutical composition comprising a nucleic acid-polysaccharide complex of  claims 1 . 
     
     
         9 . A function modulator for a Dectin-1 expressing cell, comprising a nucleic acid-polysaccharide complex of  claim 1 . 
     
     
         10 . The function modulator according to  claim 9 , wherein a function of the Dectin-1 expressing cell is an immunomodulatory function. 
     
     
         11 . An immunomodulator comprising a nucleic acid-polysaccharide complex of  claim 1 . 
     
     
         12 . A method for modulating a function of a Dectin-1 expressing cell, comprising a step of bringing a nucleic acid-polysaccharide complex of schizophyllan and polynucleotide into contact with a cell that expresses Dectin-1,
 the polynucleotide containing an siRNA to which polydeoxyadenine is added,   the siRNA being directed to a gene that affects an in vivo function for which a Dectin-1 expressing cell is responsible, and   the polydeoxyadenine having phosphodiester links that are at least partially phosphorothioated.   
     
     
         13 . The method according to  claim 12 , wherein function modulation for the Dectin-1 expressing cell is immunomodulation. 
     
     
         14 . A method for modulating an immune function, comprising administering a nucleic acid-polysaccharide complex of schizophyllan and polynucleotide to an animal in need of immune function modulation,
 the polynucleotide containing an siRNA to which polydeoxyadenine is added,   the siRNA being directed to a gene that affects an in vivo function for which a Dectin-1 expressing cell is responsible, and   the polydeoxyadenine having phosphodiester links that are at least partially phosphorothioated.   
     
     
         15 . A method of forming an immune function modulator from a nucleic acid-polysaccharide complex of schizophyllan and polynucleotide, comprising:
 adding a polynucleotide containing an siRNA to polydeoxyadenine, and   allowing the siRNA and a polysaccharide to form a complex, the polysaccharide comprising schizophyllan,   the siRNA being directed to a gene that affects an in vivo function for which a Dectin-1 expressing cell is responsible, and   the polydeoxyadenine having phosphodiester links that are at least partially phosphorothioated.